diff options
| -rw-r--r-- | clang/lib/Parse/ParseDecl.cpp | 27 |
1 files changed, 15 insertions, 12 deletions
diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp index 26ac6193bd5..5d47d3d9b80 100644 --- a/clang/lib/Parse/ParseDecl.cpp +++ b/clang/lib/Parse/ParseDecl.cpp @@ -100,18 +100,21 @@ static bool isAttributeLateParsed(const IdentifierInfo &II) { /// typequal /// storageclass /// -/// FIXME: The GCC grammar/code for this construct implies we need two -/// token lookahead. Comment from gcc: "If they start with an identifier -/// which is followed by a comma or close parenthesis, then the arguments -/// start with that identifier; otherwise they are an expression list." +/// Whether an attribute takes an 'identifier' is determined by the +/// attrib-name. GCC's behavior here is not worth imitating: /// -/// GCC does not require the ',' between attribs in an attribute-list. +/// * In C mode, if the attribute argument list starts with an identifier +/// followed by a ',' or an ')', and the identifier doesn't resolve to +/// a type, it is parsed as an identifier. If the attribute actually +/// wanted an expression, it's out of luck (but it turns out that no +/// attributes work that way, because C constant expressions are very +/// limited). +/// * In C++ mode, if the attribute argument list starts with an identifier, +/// and the attribute *wants* an identifier, it is parsed as an identifier. +/// At block scope, any additional tokens between the identifier and the +/// ',' or ')' are ignored, otherwise they produce a parse error. /// -/// At the moment, I am not doing 2 token lookahead. I am also unaware of -/// any attributes that don't work (based on my limited testing). Most -/// attributes are very simple in practice. Until we find a bug, I don't see -/// a pressing need to implement the 2 token lookahead. - +/// We follow the C++ model, but don't allow junk after the identifier. void Parser::ParseGNUAttributes(ParsedAttributes &attrs, SourceLocation *endLoc, LateParsedAttrList *LateAttrs) { @@ -262,8 +265,8 @@ void Parser::ParseGNUAttributeArgs(IdentifierInfo *AttrName, TypeParsed = true; break; } - // If the attribute has all expression arguments, and not a "parameter", - // break out to handle it below. + // If this attribute doesn't want an 'identifier' argument, then this + // argument should be parsed as an expression. if (attributeHasExprArgs(*AttrName)) break; |
